Low-Level Self-Assembly of Open Framework Based on Three Different Polyhedra:  Metal-Organic Analogue of Face-Centered Cubic Dodecaboride

2008 ◽  
Vol 130 (3) ◽  
pp. 800-801 ◽  
Author(s):  
Hyungphil Chun
Keyword(s):  
Self Assembly ◽  
Face Centered Cubic ◽  
Open Framework ◽  
Low Level ◽  
Metal Organic ◽  
Face Centered

Preparation and Characterization of the Ordered SiO2 Colloidal Crystallization Films

2008 ◽  
Vol 368-372 ◽  
pp. 1389-1391 ◽  
Author(s):  
Shuan Gui Qing ◽  
Bo Liu ◽  
Xun Liang ◽  
Hai Yang Li ◽  
Wei Zhong Lv ◽  
...  
Keyword(s):  
Self Assembly ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Assembly Method ◽  
Colloidal Crystallization ◽  
The Face ◽  
Infrared Spectrometer ◽  
Face Centered ◽  
Sio2 Spheres

Multilayer SiO2 crystals modified by alkoxysilanes were fabricated by the vertical deposition technique combined with self-assembly method. The SiO2 colloidal crystallization was prepared by the traditional Stöber-Fink-Bohn method, and modified by different alkoxysilanes to investigate the properties of the films. The films fabricated by the ordering of SiO2 spheres were investigated by infrared spectrometer, X-ray diffraction, scanning electron microscope, UV-visible spectrophotometer. The results showed that thin film is the face-centered cubic structures and the spheres are [111]-oriented.

scholarly journals Synthesis and Characterizations of SiO2-Ag Core-Shell Nanostructure Using Fatty Alcohols as Surface Modifiers

2015 ◽  
Vol 773-774 ◽  
pp. 199-203 ◽  
Author(s):  
Musdalilah Ahmad Salim ◽  
H. Misran ◽  
S.Z. Othman ◽  
Nurfatihah Mahadi ◽  
Nur Irfah Mohd Pauzi ◽  
...  
Keyword(s):  
Self Assembly ◽  
Ag Nanoparticles ◽  
Sol Gel ◽  
Amorphous Structure ◽  
Fatty Alcohols ◽  
Core Shell ◽  
Face Centered Cubic ◽  
Surface Modifiers ◽  
Face Centered ◽  
Xrd Patterns

SiO2-Ag core-shell nanostructure with silica core (SiO2) and silver shell (Ag) nanoparticles with spherical morphology were successfully synthesized using a modified self-assembly sol-gel method. Ag nanoparticles at ca.10-50 nm were successfully attached on monodispersed silica spheres (SiO2) with diameter of ca. 450 nm. Renewable resources of palm oil, derived fatty alcohols (octyl-alcohol (C8), decyl-alcohol (C10) and dodecyl-alcohol (C12)) were employed as nonsurfactant surface modifiers prior to coating with Ag nanoparticles. X-ray diffraction (XRD) patterns of calcined SiO2-Ag core-shell nanostructure prepared with surface modifiers exhibited amorphous structure of SiO2 (core) and face-centered cubic (FCC) structure of metallic Ag nanoparticles (shell). The results obtained in the present work demonstrated the feasibility of employing fatty alcohols as potential nonsurfactant surface modifiers in synthesizing SiO2-Ag core-shell.

scholarly journals Synthesis and Study of the Optical Properties of PMMA Microspheres and Opals

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2171
Author(s):  
Mayra Matamoros-Ambrocio ◽  
Enrique Sánchez-Mora ◽  
Estela Gómez-Barojas ◽  
José Alberto Luna-López
Keyword(s):  
Band Gap ◽  
Self Assembly ◽  
Photonic Band Gap ◽  
Average Diameter ◽  
Reflectance Spectra ◽  
Face Centered Cubic ◽  
Indirect Transition ◽  
Specular Reflectance ◽  
Assembly Method ◽  
Face Centered

Polymethylmethacrylate (PMMA) microspheres were synthesized by surfactant-free emulsion polymerization. These microspheres were used to obtain opals by the self-assembly method. Monomer and initiator quantities were varied systematically to monitor the size of PMMA microspheres. From SEM and DLS measurements, a trend was observed showing as the monomer and initiator amounts increased the average diameter of PMMA microspheres increased except when a minimum monomer amount was reached, for which the size of the microspheres remained practically constant. Diffuse reflectance spectra were processed by the Kubelka–Munk treatment to estimate the energy band gap (Eg) of the PMMA microspheres. It was found that PMMA microspheres present an indirect transition. From SEM micrographs, it is seen that PMMA opals photonic crystals are formed by microspheres in a uniform periodic face-centered cubic (fcc) array. Variable-angle specular reflectance spectra show that the opals possess a pseudo photonic band gap (PBG) in the visible and near-IR regions. Furthermore, it was found that PBGs shift towards larger wavelengths as the average diameter of the PMMA microspheres increases.

scholarly journals Self-assembly synthesis of precursors to potential open framework alkali earth metal–organic complexes

2014 ◽  
Vol 38 (5) ◽  
pp. 2135-2143 ◽  
Author(s):  
Louise B. Hamdy ◽  
Paul R. Raithby ◽  
Lynne H. Thomas ◽  
Chick C. Wilson
Keyword(s):  
Hydrogen Bonding ◽  
Dicarboxylic Acid ◽  
Self Assembly ◽  
Earth Metal ◽  
Alkali Earth Metal ◽  
Open Framework ◽  
Framework Materials ◽  
Organic Complexes ◽  
Metal Organic ◽  
Metal Ligand

A series of magnesium pyridinecarboxylic–dicarboxylic acid complexes, synthesised as precursors to potential framework materials, show a range of metal ligand and hydrogen bonding geometries. The pyridinedicarboxylic complexes show most promise as precursors for further syntheses.

Self-Assembly of Atomically Thin and Unusual Face-Centered Cubic Re Nanowires within Carbon Nanotubes

2015 ◽  
Vol 27 (5) ◽  
pp. 1569-1573 ◽  
Author(s):  
Fan Zhang ◽  
Pengju Ren ◽  
Xiulian Pan ◽  
Jingyue Liu ◽  
Mingrun Li ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Self Assembly ◽  
Face Centered Cubic ◽  
Face Centered

scholarly journals Fabricación y caracterización óptica de cristales coloidales de alta calidad formados por esferas de SiO2 de 225 nm de diámetro con empaquetamiento fcc crecidos por el método convectivo de auto-ensamblado de deposición vertical.

2010 ◽  
Vol 15 (2) ◽  
pp. 150 ◽  
Author(s):  
Octavio Alejandro Castañeda-Uribe ◽  
Juan Carlos Salcedo-Reyes ◽  
Henry Alberto Méndez-Pinzón ◽  
Aura Marina Pedroza-Rodríguez
Keyword(s):  
Photonic Crystals ◽  
Self Assembly ◽  
Volume Fraction ◽  
Colloidal Crystals ◽  
Optical Characterization ◽  
Bragg Diffraction ◽  
Face Centered Cubic ◽  
High Quality ◽  
Assembly Method ◽  
Face Centered

<p><strong>Objective:</strong> Fabrication and optical characterization of close-packed 225 nm SiO<sub>2</sub> -based colloidal crystals<strong>. Materials and methods:</strong> The vertical convective self-assembly method is used to grow high-quality 225 nm close-packed SiO<sub>2</sub>-based colloidal crystals. An annealing process (550°C) is made in order to improve the mechanical stability of the sample. Optical characterization is done by angle-resolved transmission spectroscopy (A-RTS) and structural characterization by Scanning Electron Microscopy (SEM). <strong>Results:</strong> Both, A-RTS and SEM, show that with the vertical convective self-assembly method, with the appropriate parameters of temperature of evaporation (60°C), volume fraction of the colloidal suspension (0.2% w/w) and acidity (pH=6), highly ordered close packed face centered cubic (fcc) SiO<sub>2</sub> based colloidal crystals are obtained. <strong>Conclusions:</strong> The growth of high-quality (long range order and defect-free) face centered cubic opal-based photonic crystals is reported.</p> <p><strong>Key words:</strong><em> </em>Photonic crystals, colloidal crystals, artificial opals, vertical convective deposition method, Bragg diffraction</p><br /><br />

Synthesis and Self-Assembly of Films Containing FeCoPt Nanoparticles

2001 ◽  
Vol 674 ◽  
Author(s):  
Min Chen ◽  
David E. Nikles
Keyword(s):  
Self Assembly ◽  
Annealing Temperature ◽  
Chemical Reduction ◽  
Average Diameter ◽  
Iron Pentacarbonyl ◽  
Face Centered Cubic ◽  
Oxidized Iron ◽  
Carbon Coated ◽  
Face Centered ◽  
Cobalt Acetylacetonate

ABSTRACTFe49Co7Pt44 and Fe40Co17Pt43nanoparticles were synthesized by simultaneous chemical reduction of platinum acetylacetonate and cobalt acetylacetonate and thermal decomposition of iron pentacarbonyl. As-prepared the particles had a disordered face-centered cubic lattice with an average diameter of 3.2 nm and were superparamagnetic. These particles were well dispersed in a 50/50 mixture of hexane and octane. The particles self-assembled into ordered superlattices when deposited onto carbon coated Cu TEM grids or onto single crystal Si (100) substrates. After vacuum annealing (from 500°C to 700 °C), the particles transformed to the tetragonal phase. The coercivity of the film strongly depended on the composition and annealing temperature. For the Fe49Co7Pt44film, coercivity of 8700 Oe and a squareness of 0.75 after annealing at 700 °C for 30 minutes. XPS shows existance of oxidized iron and cobalt on the surface of film.

scholarly journals An fcu Th-MOF Constructed from In Situ Coupling of Monovalent Ligands

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1332
Author(s):  
Ting Song ◽  
Wenlei Tang ◽  
Chuer Bao ◽  
Qiuxue Lai ◽  
Zhiyuan Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Metal Organic Frameworks ◽  
Face Centered Cubic ◽  
Reductive Coupling ◽  
Assembly Process ◽  
Cluster Surface ◽  
Metal Organic ◽  
Face Centered ◽  
And Behavior

Synthetic efforts targeting highly symmetrical metal–organic frameworks (MOFs) have always been relentless, for the symmetry of a MOF’s pore environment and overall crystal structure are relevant to the MOF’s properties and behavior. Herein, we report a novel Th-based MOF constructed from assembling highly symmetrical Th-oxo clusters via in situ reductive coupling of nitroso groups on the cluster surface. Nitroso groups have long been known to dimerize in a reversible fashion. Putting them on the monovalent ligands that decorate the Th-oxo clusters can facilitate a downstream assembly process that link the said clusters in a controllable and predictable manner, preserving the overall symmetry in the MOF product. Moreover, the assembly can be made permanent by reducing the azodioxy moiety to azo, effectively locking the symmetrical MOF form. We believe this process of assembling pre-formed Th-oxo clusters helps the overall MOF adopt a highly symmetrical topology (face-centered cubic, fcu) resembling the well-known UiO series MOFs based on tetravalent Zr/Hf.

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

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